The one thing that the scientist changes or manipulates to see how it affects something else is called the
a. dependent variableb. independent variablec. controld. hypothesis

thinking it would be d not too sure but i think it's right

the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.

the answer is :

ionic bonds are two oppositely charged ions that attract. a sodium ion has a 1 positive charge; a chloride ion has a 1 negative charge. sodium and chloride have oppostive charged ions that attract which forms an ionic bond. a chemical bond formed when two atoms share electrons is called